Organic electronic elements are elements that use organic substances to perform electrical operations. Organic electronic elements are expected to yield significant advantages, including energy conservation, low price and superior flexibility, and are therefore attracting considerable attention as potential replacements for conventional inorganic semiconductors based mainly on silicon.
Examples of organic electronic elements include organic electroluminescent elements (hereafter also referred to as “organic EL elements”), organic photoelectric conversion elements and organic transistors.
Among organic electronic elements, organic EL elements are attracting attention as potential large-surface area solid state light sources for use instead of incandescent lamps or gas-filled lamps or the like. Further, organic EL elements are also attracting much attention as the leading candidate for light-emitting displays that can replace liquid crystal displays (LCD) used in the field of flat panel displays (FPD), and actual production of such light-emitting displays is now proceeding.
In organic EL elements, research is currently being conducted into the use of a layer having charge transport properties, such as a charge injection layer or charge transport layer, between the light-emitting layer and the anode, for the purpose of improving the properties of the element such as the light emission efficiency or the lifespan of the element.
Further, the production processes for organic EL elements can be broadly classified into dry processes that use vacuum deposition or the like, and wet processes that use printing with inkjet technology or the like. Wet processes enable the size of the organic EL element to be increased more easily, and are also thought to provide higher productivity.
Examples of known organic EL elements include those mentioned below.
Patent Document 1 discloses an organic EL element which includes, between the light-emitting layer and the anode, an anode protective layer formed from a polyethylene dioxythiophene (PEDT) and a polystyrene sulfonate (PSS).
Patent Document 2 discloses an organic EL element which includes, between the light-emitting layer and the anode, a hole injection layer and/or a hole transport layer formed using a charge transport film composition containing a charge transport compound and an ionic compound.